When traffic paints for road signs, hot-melt adhesives and rubber modifiers such as carbon blacks are mixed with other materials, they are often supplied and molten in a Bunbury mixer or a melting furnace in the form of packages in films or bags.
Melt bags are a type of packaging bags which are molten along with contents in the processing of the contents into products or in the use of the products, and are uniformly dispersed in the products. The use of melt bags is expected to provide benefits such as improved disposal problems with used bags, a cleaner environment in taking the contents out of the bags, higher workability and easier weighing.
Materials for the melt bags include ethylene/acrylate copolymers (EEA), ethylene/methacrylate copolymers, ethylene/vinyl acetate copolymers (EVA), resins obtained by compounding these copolymers with a small amount of polyethylene, and ethylene/α-olefin copolymers (for example, Patent Documents 1 to 4).
However, the melt bags formed of these materials cannot be molten uniformly at below melting operation temperatures and remain unmolten in the final products, deteriorating the appearance and properties. Further, these melt bags are still unsatisfactory in storage stability when filled with contents or in mechanical properties of the melt bags.
Patent Document 1: JP-A-2005-219818
Patent Document 2: JP-A-2005-170428
Patent Document 3: JP-A-2004-2581
Patent Document 4: JP-A-2000-355359